WinUSB bulk in/out device

[rundekugel]

I created an small embedded WinUSB device which offers 2 bulk endpoints. This device can communicate with Linux and with Windows10 without installing driver, or a .inf file. And it's not recognized as serial com port.

Now I try to build an embedded Linux gadget with your libusbgx. It must respond to OS_DESC (0xee) as WinUSB device. And must not be recognized as serial com port. It shall behave like a g_serial with param "use_acm=no"

If I build it with filesystem commands. Then the os_desc setting in Window10 it's recognized in registry settings

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\usbflags<VIDPID>
osvc = 01 bc
SkipContainerIdQuery = 01 00

But not recognized as WinUSB device

It looks like, the os_desc feature does only fully work for RNDIS.

This is the respond to vendor request, which works when I send it from my embedded WinUSB to Windows:

const U8 u8ExtendedCompatIDOSFeatDesc[] =
{
0x28, 0x00, 0x00, 0x00, /* dwLength Length of this descriptor / //(40 bytes)
0x00, 0x01, / bcdVersion = Version 1.0 /
0x04, 0x00, / wIndex = 0x0004 /
0x01, / bCount = 1 /
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, / Reserved /
0x00, / Interface number = 0 /
0x01, / Reserved /
0x57, 0x49, 0x4E, 0x55, 0x53, 0x42, 0x00, 0x00, //string = "WINUSB"
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, / subCompatibleID /
0x00, 0x00, 0x00, 0x00, 0x00, 0x00 / Reserved */
};

I tried with a modified example of your code:
myWinusbGadget.zip
diff:
winusb-diff.zip

I get error when trying to usbg_set_interf_os_desc() :

Error setting function OS desc
Error: USBG_ERROR_NOT_FOUND : Not found (file or directory removed)

How can I make it working for gser ? Is it possible with changing your src? Or do I have to change the kernel gadget files?
Can you help me to add this feature to your lib?

[pabs3]

@rundekugel are you able to trace the usbg_set_interf_os_desc in a debugger to find out where the USBG_ERROR_NOT_FOUND error is coming from? The function itself does not set that error, but other functions might do that.

[rundekugel]

@pabs3 sorry, I found no time to trace the issue.
I used https://github.com/rundekugel/gadgetfsd/tree/WinUSB to get my project running.
If I can help by answering any questions about WinUSB, don't hesitate to ask.

[pabs3]

Please let us know if you find time to trace the issue.

I think you have provided enough info about WinUSB, thanks.

For the sake of completeness, which versions of the Linux kernel are you finding the error on? Have you tried the most recent ones (5.15-rc1 right now or 5.14.5 stable)?

Unfortunately I don't have any physical USB UDC gadget devices nor do I have a Windows install, so I won't be able to debug this either.

[rundekugel]

I'm sorry, I don't find time to trace the issue.